CN115685415A

CN115685415A - Lens assembly, camera module and method of manufacturing lens assembly

Info

Publication number: CN115685415A
Application number: CN202210855234.9A
Authority: CN
Inventors: P·C·冈萨雷斯; S·查玛多伊拉; J·C·阿里亚斯; I·S·艾莉兹; E·C·查马罗; C·H·维拉
Original assignee: Ficosa Adas SL
Current assignee: Ficosa Adas SL
Priority date: 2021-07-23
Filing date: 2022-07-20
Publication date: 2023-02-03
Also published as: US20230038551A1; EP4123357A1

Abstract

The present application relates to a lens assembly, a camera module and a method of manufacturing a lens assembly. The camera module (200) has a lens assembly (100), the lens assembly (100) comprising a body (110) and a heating element (300), the heating element (300) having an optically transparent coating (310) applied to the body (110) for heating the body to remove water-based obscuration when an electrical current is passed through. The module comprises a power supply (400) and a lens barrel (119), the power supply (400) for supplying an electric current to the optically transparent coating (310) through a conductor (450), the lens barrel (119) for receiving the body (110), the body (110) comprising a channel (220) for the conductor (450) extending within the lens barrel (119) towards the lens body (110). The method includes applying high and low index layers (322, 321) and an aluminum-doped zinc oxide layer (330) to a lens body (110).

Description

Lens assembly, camera module and method of manufacturing lens assembly

Technical Field

The present invention relates generally to a camera module, a lens assembly for a camera module, and a method for manufacturing a lens assembly, in particular, but not exclusively, in the automotive field.

Background

Camera modules are widely used in the automotive field for capturing images from outside of motor vehicles, such as rear view mirrors, reversing cameras, forward-looking cameras, rear-looking cameras, etc. Known camera modules include a lens assembly that includes a lens body having at least one lens element mounted to a lens housing or lens assembly holder. The camera module also includes an image sensor or imager in optical communication with the lens body. The image sensor should be arranged in alignment with the lens body to obtain a suitable image quality.

At least a portion of the surface of the lens body is arranged to face the outside of the motor vehicle and is therefore susceptible to external moisture from the air. This causes optical interference or contamination, making the image captured by the camera module unclear. Furthermore, when the ambient temperature drops, external moisture may freeze, so that a layer of ice may be generated that adheres to the lens surface, at least partially blocking the captured image.

Various attempts have been made in the art to remove water-based barriers that may adhere to the lens surface. For example, in order to heat the lens surface, it has been proposed to provide a heating device in the camera module.

EP1626583 in the name of the present applicant discloses an image acquisition unit for monitoring the exterior of a vehicle, which image acquisition unit comprises heating means for providing thermal energy to a transparent element.

Camera modules are known in the art, which comprise a cartridge housing or lens assembly holder for receiving a lens assembly and heating means arranged on an outer circumferential surface of the cartridge housing for heating the lens. The heating device is configured as a non-transparent ring that is secured to the inner surface of the cartridge housing. Therefore, a gap is undesirably generated between the ring of the heating device and the outer circumferential surface of the lens body (particularly, the lens barrel of the lens body). This causes problems in the prior art camera modules. In order to obtain a high optical efficiency for good image quality and an electrical conductivity for a suitable lens heating effect, the gap between the heating means and the surface of the lens assembly should be as small as possible. However, in practice, reducing the gap is difficult to achieve because it is formed due to manufacturing tolerances and assembly processes of the camera module, which cannot be avoided. In addition, if the heating device is not properly positioned, the lens housing may be heated by conduction without undesirably reaching and damaging electronic components disposed therein, such as a Printed Circuit Board (PCB). If the PCB is heated excessively, buckling and bending may cause the imager to be moved, resulting in undesirable misalignment with respect to the lens body.

The above and other deficiencies found in the prior art are overcome by the lens assembly, camera module and method of the present invention.

Disclosure of Invention

In a first aspect of the present disclosure, a lens assembly is provided. The lens assembly includes a lens body and a heating element. The heating element in the present lens assembly comprises an optically transparent coating comprising an optically transparent electrically conductive layer. The optically clear coating is applied to at least a portion of the lens body.

The optically transparent conductive layer may be a uniform (e.g., continuous) layer, but alternatively it may be a non-uniform (e.g., discontinuous) layer, as desired. Furthermore, the optically transparent electrically conductive layer forming the heating element may partially or completely cover at least a portion of the surface of the lens body, e.g. the front or outer surface thereof.

The optically transparent coating is intended for resistive heating of at least a portion of a lens body when an electric current is flowing through the at least a portion of the lens body. This allows any water-based obstructions (e.g., at least one of fog, condensate, snow, and ice) that may adhere to the lens body to be effectively removed.

As used herein, the terms "coating" and "layer" refer to a sheet of material applied to a surface of at least a portion of an object, such as a lens or a cover provided to protect a lens.

Preferably, the optically transparent conductive layer comprises at least aluminum-doped zinc oxide (AZO). Although AZO is the most preferred conductive element, other suitable materials for the optically transparent conductive layer can be used, such as Indium Tin Oxide (ITO), indium zinc oxide, and any other transparent conductive metal oxide.

The optically clear coating can further comprise at least one optically clear back layer and at least one optically clear front layer. The at least one optically transparent back layer is disposed between the lens body and the optically transparent conductive layer. The at least one optically transparent front layer is arranged on top of the optically transparent electrically conductive layer. In one example, multiple optically transparent back layers may be combined with an optically transparent conductive layer and a single optically transparent front layer. Other different configurations are possible for purposes of this disclosure.

According to an advantageous example, the optically transparent back layer is an optical anti-reflection or anti-reflection layer adapted to eliminate or at least reduce reflection from the lens body. In particular, the optically transparent backing layer may comprise at least one high refractive index layer and at least one low refractive index layer.

As is known in the optical arts, refractive index (refractive index or index) is a dimensionless value that corresponds to a measure of the bend of a ray of light when passing through different media, that is, how much the path of light is bent or refracted when entering a material. For example, a refractive index of water of 1.333 means that light travels 1.333 times slower in water than in a vacuum. Increasing the refractive index corresponds to decreasing the speed of light in the material.

The high refractive index layer may have a high refractive index. Further, the high refractive index layer may preferably include a metal material that is non-conductive and optically transparent or an optically transparent metal oxide having low conductivity, such as titanium oxide (TiOx). The low refractive index layer may have a low refractive index. Further, the low refractive index layer may preferably comprise an optically transparent dielectric material, such as silicon dioxide (SiO 2). Other materials for the high index layer and the low index layer are possible.

The meaning of high and low refractive index in the field of optics will be readily recognized by those skilled in the art. Thus, within the meaning of the present disclosure, a high refractive index corresponds to a refractive index of more than 1.65, more preferably between 1.7 and 2.9, and still more preferably between 2.0 and 2.4. The low refractive index corresponds to a refractive index lower than 1.65, preferably lower than 1.60, more preferably between 1.3 and 1.65, and even more preferably between 1.4 and 1.5.

For example, siO at 550nm wavelength ₂ Has a refractive index of 1.44-1.52, a refractive index of TiOx of 2.2-2.5, and a refractive index of AZO of 1.8-1.86.

Typically, the optically transparent back layer of the lens assembly comprises a plurality (preferably pairs) of alternating low refractive index and high refractive index layers to form an optically transparent back layer, thereby creating an effective antireflective multilayer coating.

For optically transparent coatings of 10-1000nm thickness, the following thicknesses are preferred for the different layers.

The conductive layer, e.g. AZO, is preferably 10-900nm thick, preferably 20-600, more preferably 20-350, even more preferably 70-300nm. Low refractive index layer, e.g. SiO ₂ Preferably 9-90nm thick, preferably 20-40nm. The high refractive index layer, such as TiOx, is preferably 2-30nm thick, preferably 5-30nm thick, more preferably 5-15nm thick, more preferably 5-10nm thick. Optically transparent front layers, e.g. SiO ₂ Preferably 10-200nm thick, preferably 50-150nm.

The above thicknesses may be provided alone or in combination. The above thicknesses have proven advantageous for the production of optically transparent coatings with electrically conductive and antireflective properties in the visible range from 400nm to 750 nm.

It may be advantageous if one or more of the layers making up the optically clear coating are applied to the lens body by Physical Vapor Deposition (PVD) as is known in the art for making thin films and coatings. That is, the optically transparent, electrically conductive layer may be applied by Physical Vapor Deposition (PVD), and other layers such as a high refractive index layer, a low refractive index layer, and/or at least one optically transparent front layer may also be applied by Physical Vapor Deposition (PVD). The area of the lens body, in particular the front surface thereof, may be covered, for example, by 0.5-5cm ² Preferably 2cm ² 。

The lens body may include a front surface, a rear surface, and side surfaces. In use, the front surface is arranged to face away from the rear surface, and the side surfaces abut the front and rear surfaces. The side surface may further include at least a portion substantially parallel to the optical axis. The optical axis may be defined as a theoretical line passing through the centers of the lens and the image sensor. The side surface of the lens body may include a lateral surface through which the optical axis does not pass. The front and rear surfaces of the lens body are surfaces through which the optical axis passes.

An optically clear coating can be applied to at least a portion of one or more of the anterior, posterior, and side surfaces of the lens body.

In a preferred example, the optically transparent coating is disposed on the front and/or back surface of the lens body, and is typically disposed on at least one surface of the lens body through which the optical axis passes.

Preferably, the optically transparent coating is arranged on both surfaces of the lens body, and more preferably, the optically transparent coating is arranged on both mutually adjacent surfaces of the lens body. More preferably, the optically transparent coating is arranged on at least a part of the surface of the lens body traversed by a lens optical axis and on at least a part of the surface of the lens body not traversed by the lens optical axis. For example, it may be the case that the optically transparent coating is arranged both on at least a part of the front surface and on at least a part of the side surface of the lens body.

The location of the lens body where the optically clear coating is applied may depend on the radius of curvature of the outer surface of the lens body. In the case of a lens body having a large radius of curvature (i.e., an almost flat lens body), the optically clear coating can be seamlessly applied to the front surface thereof. The optically clear coating may preferably be applied anywhere other than the front surface of the lens body, such as the rear or side surface of the lens body, as the curvature of the front surface of the lens body increases.

Preferably, the optical transparency is applicable to at least one of:

(i) A portion of the front surface and a portion of the side surface of the lens body; or

(ii) A portion of the rear surface and a portion of the side surface of the lens body.

The lens body may include a plurality of lens elements and a lens barrel. In use, the plurality of lens elements are aligned to direct light from one lens element to another lens element to reach the image sensor or imager when the lens assembly is properly mounted in the camera module. Thus, the lens body may include two or more lens elements configured as an array of optically transparent members (such as glass or plastic sheets) arranged in a particular order to allow light to pass from one end to the other and ultimately into the camera module housing in which the image sensor is arranged. In preferred examples, the lens body may comprise four, five or six lens elements. Of course, a different number of lens elements is also possible.

A plurality of lens elements are accommodated in the lens barrel. The lens barrel may be a tube shaped to enclose the plurality of lenses. Accordingly, the lens barrel may be part of a lens body and may be manufactured from a wide variety of materials ranging from plastics to metals.

The plurality of lens elements may include at least one lens element having the above-described configuration. That is, each lens element of the plurality of lens elements may include a front surface, a back surface, and a side surface. The front surface of the lens element may be arranged facing away from the rear surface. The first lens element of the plurality of lens elements may be an outermost lens element of a vehicle on which the lens element is mounted. The first element may comprise an outer surface, which may be a front surface that may be at least partially surrounded by an external environment of the camera module. In use, when the lens assembly is attached to the camera module, the outer surface of the first element may be the surface of the lens assembly furthest from the image sensor. The back surface may in turn comprise a first portion, which may be substantially perpendicular to the optical axis, and a second portion, which may be a curved portion. Further, the side surface may abut the front surface and the rear surface. The side surfaces of the lens body may include a plurality of lateral surfaces, wherein the optical axis may not pass through the lateral surfaces. Further, at least a portion of the side surface may be substantially parallel to the optical axis.

The second portion of the rear surface and the front surface of the lens element are surfaces through which the optical axis of the lens passes. The side surface of the lens element may include a lateral surface through which the optical axis does not pass. The side surface may comprise at least one lateral surface that may be substantially parallel to the optical axis.

The first portion of the back surface may comprise a surface arranged at least substantially perpendicularly to the optical axis, the optical axis not passing through the surface.

An optically clear coating can be applied to at least a portion of one or more of the front surface, side surface, and back surface of the first lens element of the lens body. Preferably, an optically clear coating may be applied to at least a portion of two or more of the following surfaces of the first lens element: a front surface, a side surface, and a rear surface. It has been found to be advantageous to apply an optically clear coating to at least two surfaces, and more preferably to at least two adjacent surfaces of the lens element, because the time required to heat the front surface is reduced, and thus the time to remove any water-based obscuration that may adhere to the front surface is advantageously reduced.

As mentioned above, it is preferred that the optically clear coating is applied to at least one of:

(i) A portion of the front surface and a portion of the side surface of the first lens element; or

(ii) A portion of the first portion of the rear surface and a portion of the second portion of the rear surface of the first lens element.

More preferably, the optically clear coating may be applied to at least:

(a) A portion of the front surface, a portion of the side surface, and a portion of the first portion of the back surface of the first lens element; or

(b) A portion of a first portion of a back surface, a portion of the second portion of the back surface, and a portion of the side surface of the first lens element.

Preferably, the heating element further comprises a conductor for supplying an electrical current to the optically transparent conductive layer for resistive heating of at least a portion of the lens body. The conductor is arranged to electrically connect a power source to the transparent conductive coating to feed current to the transparent conductive coating. Suitable conductors may be aluminium or copper cables, or layers made of conductive materials such as ITO or AZO. For example, for Direct Current (DC) devices, two conductors are provided to close the circuit.

Preferably, the heating element may further comprise attachment means for attaching the conductor to the optically transparent coating, such that the conductor may be electrically connected to the optically transparent electrically conductive layer.

More preferably, the attachment means may be arranged on the first portion of the rear surface and/or the lateral surface of the first lens element.

In some cases, the optically clear coating may not be applied directly to the lens body but to the intermediate portion. For example, the cover glass may be provided onto the lens body, in which case the transparent conductive coating is applied to the cover and thus not directly to the lens. In this case, the area of the lens body covered by the transparent conductive coating may vary. Thus, the optically clear coating can be applied to the cover (if provided), or to the lens body if the cover is not provided. In the latter case, both the cover and the lens body may be referred to herein as an optical element.

A camera module for a motor vehicle is also described herein. The camera module includes a housing defining an interior space therein, an optically transparent external optical element, an optically transparent internal optical element, a heating element, and an electronic carrier including an image sensor. The housing also includes a cartridge housing. The camera module further includes a lens assembly including a lens body and a heating element. The lens body may be part of at least one of the external optical element and the internal optical element.

The camera module may further comprise a cover as described above for covering the above-mentioned lens assembly. The cover may be made of plastic, glass or any other suitable material. If the camera module comprises a cover, the cover corresponds to the external optical element and the lens body corresponds to the internal optical element. If the camera module does not comprise a cover, the first lens element of the lens body corresponds to the external optical element and the second lens element of the lens body corresponds to the internal optical element.

The camera module may comprise a power supply for the heating element, or the heating element may be supplied with power from an external power supply.

The camera module housing may comprise a first housing part, a second housing part and engagement means for engaging the first and second housing parts together to define a first interior space. Such a first interior space is adapted to accommodate an electronics component, such as an electronics carrier, which may include an image sensor or imager therein. The first housing part may be a front housing, wherein the second housing part may be a rear housing.

The cartridge housing is configured for at least partially receiving the lens assembly. The lens assembly is inserted into and attached to the cartridge housing at least in part by threads, adhesive (such as glue), or by any other suitable attachment means. The inner wall of the cartridge housing may define a second interior space. The cartridge housing may be part of or attached to the front housing. The cartridge housing extends longitudinally from a first end to a second end. The cartridge housing includes a bottom surface disposed at or near the second end, a top surface disposed at or near the first end defining an opening, and one or more sidewalls including an inner surface. A space is formed in the interior of the cartridge housing. The lens assembly is at least partially arranged in a space formed in the interior of the cartridge housing, hereinafter referred to as the above-mentioned second interior space.

Preferably, the cartridge housing may be cylindrical or substantially cylindrical, particularly adapted to at least partially receive the lens assembly. The cartridge housing may comprise a top side defining an opening, wherein in use the lens assembly is received by the housing with the one or more lens elements of the lens body received by the wall of the cylindrical cartridge. Preferably, in use, a side surface and/or a rear surface of the lens body is arranged in the second interior space. More preferably, in use, a side surface and/or a rear surface of the first lens element is arranged in the second interior space.

The camera module further comprises an image sensor for receiving light passing through the lens elements of the lens body. The image sensor is coupled to the electronic carrier located in the first interior space, wherein the image sensor is configured to generate an electronic signal based on the received light.

The heating element comprises an optically transparent coating comprising an electrically conductive layer or an optically transparent electrically conductive layer having at least some of the above-described features. The optically transparent conductive layer is applied to at least a portion of the lens body to resistively heat the optically transparent conductive layer when current flows through the optically transparent conductive layer to remove any water-based obstructions that may adhere to the lens body.

The power supply may be selected to provide a suitable voltage of 6-36 volts (V), more preferably 12-24V, and still more preferably 12V, to the coating. The power source may be part of or connected to the electronic carrier. The electronic carrier may in turn comprise one or more Printed Circuit Boards (PCBs). In case the electronic carrier comprises two or more printed circuit boards, the power supply may be arranged on the same printed circuit board to which the image sensor is coupled, or alternatively on other printed circuit boards. Alternatively, the power supply may be arranged outside the camera housing. If the power supply is arranged outside the camera housing, it may preferably be part of or connected to an Electronic Control Unit (ECU) of a Camera Monitoring System (CMS) or a digital rear view mirror.

The lens assembly may further comprise attachment means for attaching the above-mentioned conductors to the optically transparent coating layer while electrically connecting the conductors to the optically transparent conductive layer. Preferably, the heating element of the lens assembly may comprise two or more conductors and at least one attachment means for attaching a preferred end of each conductor to the optically transparent coating and electrically connecting the conductor to the optically transparent electrically conductive layer, such that an electrical current may flow through at least one layer of the optically transparent coating.

The attachment means may be an adhesive, preferably a conductive adhesive, such as a fluid adhesive comprising polymer and metal particles. More preferably, the adhesive may be an epoxy-based adhesive and metal micro (metallic micro) and/or nano-particles. Thus, the conductor may be attached to the optically transparent coating by means of an adhesive joint (e.g. glue). When a fluid adhesive is used, the adhesive is in a first pre-cured state prior to application, which is a liquid, and then once the adhesive is applied, the adhesive is in a second cured state, which is no longer a liquid. This results in better mechanical and electrical bonding characteristics than are achieved in conventional prior art devices where the attachment means are used based on welding or screws.

At least one channel is formed in the housing of the camera module, in particular in the front housing of the camera module. More specifically, the at least one passage may at least partially pass through the cartridge housing. The channel is configured to receive a conductor for electrically connecting a power source and the optically transparent conductive layer. The channel is advantageously arranged to extend between the inner and outer walls of the cartridge housing towards the lens body. In use, the conductors pass through the channels without affecting the captured image from the lens assembly to an image sensor or imager disposed in the camera module.

In a second aspect of the present disclosure, a method for manufacturing a lens assembly is provided. As described above, the lens assembly includes a lens body and a heating element. The method includes applying to at least a portion of one or more of the anterior, posterior, lateral and posterior surfaces of the lens body: at least one high refractive index layer, at least one low refractive index layer applied to the high refractive index layer, and at least one optically transparent electrically conductive layer, which faces the outside of the motor vehicle, wherein the transparent conductor layer, which may comprise aluminum-doped zinc oxide, is applied to the low refractive index layer. In addition, the method includes applying an optically transparent front layer including a low refractive index material onto the transparent conductor layer. Further, an optically clear coating is applied to the lens body by Physical Vapor Deposition (PVD).

The camera module is assembled by at least partially inserting the lens assembly with the optically transparent coating already applied into the lens housing and accurately moving the lens body until proper alignment with the image sensor is achieved. Preferably, the calibration process may be performed when the lens assembly is assembled into the lens housing. The image sensor remains coupled to a Printed Circuit Board (PCB) in suitable optical communication, which is aligned with the lens assembly so that images of the exterior of the vehicle are properly captured.

The camera module with the above-described lens assembly having an optically transparent coating does not interfere with the optical performance of the camera, both when it is heating the lens and when it is not heating the lens.

Drawings

Non-limiting examples of camera modules will be described below with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional detail view of an optically clear coating on a portion of an optical element;

fig. 2 to 7 are graphs showing normalized reflectance in different examples of optically transparent coatings having different layer thicknesses versus different wavelengths of visible light;

FIGS. 8A-8E are cross-sectional views of a lens body showing different examples of surfaces of the lens body in which an optically clear coating is applied;

FIG. 9 is a diagrammatic detail view depicting the surface of a lens body to which an optically clear coating may be applied according to the example in FIGS. 8A-8E;

fig. 10A to 10C are cross-sectional views of the camera module of the present invention, showing different arrangements of the channels for the conductors;

fig. 11A shows a camera module with a protective cover;

fig. 11B shows the camera module without the protective cover; and

fig. 12 shows a camera module comprising a speckle detection system and a heating means.

Detailed Description

One example of a camera module 200 is schematically shown in the non-limiting examples shown in fig. 10A to 10C, 11A to 11B, and 12.

The camera module 200 shown may be mounted to a rear view mirror, for example, for capturing images from outside the motor vehicle. Other applications are of course not excluded, such as a surrounding vision system, a reverse camera for parking, or a forward and rear view camera.

The camera module 200 includes a lens assembly 100, the lens assembly 100 including a lens body 110 and an image sensor or imager 470. The image sensor 470 is attached to an electronic carrier, in particular, to the top surface of a Printed Circuit Board (PCB) 460. The image sensor 470 is in optical communication with the body 110 and is arranged to be aligned with the body 110 along the optical axis O of the lens assembly 100, as shown in fig. 10A-10C, 11A-11B, and 12.

The lens assembly 100 further comprises a heating element 300, the heating element 300 being adapted to heat a portion of the lens body 110 when an electric current is flowing through said portion of the lens body 110, as will be explained in detail below.

As shown in fig. 1, the heating element 300 includes an optically clear coating 310. Depending on the optical and heating requirements, the optically clear coating 310 can have uniform and/or continuous or non-uniform and/or discontinuous properties. Optically transparent coating 310 also includes an optically transparent conductive layer 330, and optically transparent conductive layer 330 can have uniform and/or continuous or non-uniform and/or discontinuous properties, depending on optical and heating requirements.

The optically transparent coating 310 comprises an optically transparent layer 320 applied directly to the front surface 111 of the lens body 110. The optically transparent back layer 320 is adapted to eliminate or at least reduce reflections from the front surface 111 of the lens body 110 due to the heating action of the electrical current flowing through the lens body 110.

With continued reference to fig. 1, the optically transparent conductive layer 330 of the optically transparent coating 310 comprises at least aluminum doped zinc oxide (AZO). If the optically transparent coating 310 does not include the optically transparent back layer 320 described above, the optically transparent conductive layer 330 is applied directly to the lens body 110.

Optically clear coating 310 configured as shown in fig. 1 allows resistive heating of a portion of lens body 110 as electrical current flows therethrough. This allows any water-based obstructions, such as at least one of fog, condensate, snow, and ice (which may adhere to the lens body 110), to be effectively removed without affecting the optical performance of the camera module 200.

The thickness of the transparent conductive AZO layer 330 has a significant effect on the joule effect for effectively heating the lens body 110. The thickness of the AZO layer 330 of the optically transparent coating 310 is sufficiently large for low resistance and short heating time of the lens body 110. On the other hand, the thickness of the transparent conductive AZO layer 330 is small enough for the low reflectivity of the lens body 110 for good image quality and security.

Continuing with fig. 1, the optically transparent back layer 320 in turn comprises a high refractive index layer 321 and a low refractive index layer 322 applied directly to the front surface 111 of the first lens element 110 a. A transparent conductive AZO layer 330 is applied directly to the low refractive index layer 322.

The high refractive index layer 321 has a refractive index higher than 1.65. The refractive index of the high refractive index layer 321 is preferably between 1.7 and 2.9, and more preferably between 2.0 and 2.4. The high refractive index layer 321 is formed of any metal oxide, which is titanium oxide (TiOx) according to the example described above.

As also shown in FIG. 1, low index layer 322 is made of silicon dioxide, siO, having a refractive index of less than 1.65 ₂ And (4) forming. The refractive index of the low refractive index layer 322 is preferably lower than 1.60,and more preferably between 1.3 and 1.65, and even more preferably between 1.4 and 1.5. Low index layer 322 is applied directly to high index layer 321.

One or more of optically transparent backing layer 320 and optically transparent conductive layer 330, high refractive index layer 321 and low refractive index layer 322 comprising optically transparent coating 310, are applied to the lens body by Physical Vapor Deposition (PVD).

Referring to fig. 8A to 8E, the lens body 110 includes a plurality of

lens elements

110a, 110b, 110c, 110d, 110E, 110f and a lens barrel 119. The plurality of

lens elements

110a, 110b, 110c, 110d, 110e, 110f are aligned along the optical axis O to direct light from one lens element to another in order to reach the image sensor 470. The plurality of

lens elements

110a, 110b, 110c, 110d, 110e, 110f are accommodated within a lens barrel 119. The lens barrel 119 is a tubular member that encloses a plurality of

lens elements

110a, 110b, 110c, 110d, 110e, 110f therein.

Reference will be made below to the body 110 and

lens elements

110a, 110b, 110c, 110d, 110e, 110f for reference to the same elements of the lens assembly 100.

As shown in fig. 9 of the drawings, the first lens element 110A has a rear surface including a first portion 113 and a second portion 114, the first portion 113 being flat and substantially perpendicular to the optical axis O, the second portion 114 being convex and curved outwardly, away from the imager 470, as shown in fig. 10A to 10C, 11A and 11B, and 12. The lens element 110a has side surfaces 112 that extend into the front surface 111 and the

rear surfaces

113, 114. The optical axis O does not pass through the side surface 112 of the first lens element 110 a. The side surface 112 of the first lens element 110a may include a plurality of lateral surfaces through which the optical axis may not pass (not shown).

The second portion 114 of the rear surface and the front surface 111 of the first lens element 110a are surfaces through which the lens optical axis O passes. The side surface 112 of the first lens element 110a includes at least one lateral surface substantially parallel to the optical axis O.

The first portion 113 of the rear surface of the first lens element 110a may comprise a surface arranged at least substantially perpendicular to the optical axis O, which does not pass through the surface.

As shown in FIGS. 8A-8E of the drawings, optically clear coating 310 covers the front or outer surface 111 of the lens body 110, corresponding in the non-limiting example shown to 2cm of the lens body 110 ² Surface area of (a). However, other values for the surface area of the lens body 110 covered by the optically clear coating 310 can be in the range of 0.5-10cm ² Within the preferred ranges of (a).

In one example, the optically clear coating 310 can completely or partially cover the front or outer surface 111 of the lens body 110 and/or other different portions of the lens body, such as the rear surface 114, side surfaces 112, rear surface 113, and rear surface 114 of the lens body 110 shown in fig. 9 of the drawings. In another example, the optically clear coating 310 can completely or partially cover the protective outer cover 150 as will be described below with reference to fig. 11A of the drawings.

Reference is now made to fig. 8A to 8E of the drawings.

In the example shown in fig. 8A, the optically transparent coating 310 completely or partially covers the front or outer surface 111, the

rear surfaces

113, 114 of the lens body 110, and the side surfaces 112 of the lens body 110. In the example shown in fig. 8B of the drawings, the optically transparent coating 310 completely or partially covers the front or outer surface 111 of the lens body 110, the side surfaces 112 of the lens body 110, and the rear surface 113 of the lens body 110. In the example shown in fig. 8C of the drawings, the optically clear coating 310 completely or partially covers the rear surface 113, the rear surface 114 of the lens body 110, and the side surfaces 112 of the lens body 110.

In the example shown in fig. 8D, the optically transparent coating 310 completely or partially covers the front or outer surface 111 of the body 110 and the side surfaces 112 of the body 110.

In the example shown in fig. 8E, the optically clear coating 310 completely or partially covers the

rear surfaces

113, 114 of the lens body 110 and the side surfaces 112 of the lens body 110.

In the example shown in fig. 8A to 8E, the optically transparent coating 310 is preferably arranged on any two mutually

adjacent surfaces

111, 112, 113, 114 of the lens body 110.

As already explained before, the refractive index (refractive index or refraction index) is known as a dimensionless value that corresponds to a measure of the bending of a ray of light when passing through different media, that is, how much the path of the light is bent or refracted when entering a material. For example, a refractive index of water of 1.333 means that light travels 1.333 times slower in water than in a vacuum. Increasing the refractive index corresponds to decreasing the speed of light in the material.

On the other hand, it is also known in the field of optics that the reflection is a change of direction of the electromagnetic wave front at the interface between two different media, so that the wave front returns into the medium from which it originates. In general, it is acceptable that an optical material such as glass may have an approximate reflectivity of 4% per interface. Thus, an optical material with two interfaces may have a reflectivity of about 8%.

The above-described arrangement of the layered configuration of optically transparent coating 310 is crucial to enhance a good compromise between maximum optical transparency for image acquisition and optimal electrical conductivity for lens heating. The above configuration allows sufficiently high power to be supplied to heat the lens quickly, for example within 8-10 seconds, to melt ice adhering to the lens, for example but not too high (e.g. below 60 ℃), so that if someone touches and damages the lens while the vehicle is stopped, safety is not compromised to avoid burns. A good balance between light transmission (low reflectivity), heating speed and safety is provided.

TABLE 1

Table 1 below shows eight different examples of different layer thicknesses corresponding to the

different layers

321, 322, 330, 340 of the optically transparent coating 310 in case an additional optically transparent front layer 340 is provided on the transparent conductive AZO layer 330. The optically transparent front layer 340 is a low refractive index silicon dioxide layer and is made of silicon dioxide SiO with a refractive index lower than 1.65 ₂ And (4) forming.

The refractive index of the front layer 340 is preferably below 1.65, more preferably below 1.60, and still more preferably between 1.3 and 1.65, and even more preferably between 1.4 and 1.5. As shown in fig. 1, the front layer 340 is applied directly onto the optically transparent conductive layer 330.

As shown in table 1, it is preferable that the low refractive index layer 322 is thicker than the high refractive index layer 321. Specifically, the low refractive index layer 322 is at least twice as thick as the high refractive index layer 321. In particular, low index layer 322 is between 1.2 times and 15 times thicker than high index layer 321. More specifically, the low refractive index layer 322 is between 1.5 times and 10 times thicker than the high refractive index layer 321, and more specifically, between 2 times and 5 times thicker.

Preferably, the AZO layer 330 is thicker than the high refractive index layer 321 and the low refractive index layer 322. In particular, it is preferred that the AZO layer 330 be at least twice as thick as the optically transparent back layer 320. For example, AZO layer 330 may be at least twice as thick as low refractive index layer 322. More specifically, the AZO layer 330 is at least five times thicker than the high refractive index layer 321. In particular, AZO layer 330 is between 2 and 20 times thicker than low refractive index layer 322. More specifically, AZO layer 330 is between 2 times and 15 times thicker than low refractive index layer 322, more preferably between 2.5 times and 8.5 times thicker in particular.

Preferably, the front layer 340 is thicker than the high refractive index layer 321. In particular, the front layer 340 may be at least twice as thick as the optically transparent back layer 320. Further, the front layer 340 is thicker than the low refractive index layer 322. In particular, the front layer 340 is at least twice as thick as the high refractive index layer 321. More specifically, front layer 340 is at least three times thicker than low refractive index layer 322. In particular, front layer 340 is between 2 and 6 times thicker than low refractive index layer 322. More specifically, front layer 340 is between 2 and 5 times thicker than low refractive index layer 322, and more specifically, between 2.5 and 4 times thicker.

Fig. 2 to 7 are graphs showing normalized reflectance of the lens body 110, wherein the front surface 111 and the

rear surfaces

113, 114 are coated with an optically transparent coating 310, at different values of the wavelength of light. Fig. 2, 3, 4, 5, 6, and 7 correspond to data from examples 2, 4, 5, 6, 7, and 8, respectively.

In view of the experimental results shown in table 1, the following thicknesses of the optically transparent coating layer 310 are preferable for the visible light range of 430nm to 700 nm:

-a transparent conductive (AZO) layer (330): 50-350nm;

low refractive index (SiO) ₂ ) Layer (321): 9-90nm, preferably 20-40nm;

-a high refractive index (TiOx) layer (322): 5-15nm, preferably 5-10nm; and

low refractive index (SiO) ₂ ) Layer (340): 9-90nm, preferably 20-40nm.

The combination of the thicknesses of the

layers

321, 322, 330, 340 shown in table 1 has been shown to provide good optical performance in terms of low reflectivity, as can be seen in fig. 2-7. Fig. 2 to 4 and 7 correspond to examples 2, 4, 5 and 8, wherein the reflectivity is below 4% and even below 2% for most of the electromagnetic spectrum visible to the human eye. In particular, fig. 4, corresponding to example 4, shows that the reflectance is below 1% for most of the visible spectrum. On the other hand, fig. 5 and 6, corresponding to examples 5 and 7 respectively, show that for most of the visible spectrum reflectance, the reflectance is below 2%, except in the range between 0.4 and 0.45nm, where the reflectance is between 8% and 2%. For these particular examples and this particular range, it is assumed that this unwanted value of reflection is due to experimental error in depositing the coating. In fact, for each configuration, the expected reflectivity is below 2%, and the small deviations shown in the graphs are experimental in nature.

If the body 110 is not coated with the optically clear coating 310, the undesired reflection of light may be reflected by the surface of the body 110, which may be approximately 4%. Furthermore, anti-reflective coatings are well known and widely used on the surface of optical elements (e.g. lens elements or covers) to reduce unwanted reflections, however, known anti-reflective coatings do not comprise any conductive transparent layer 330, such as AZO layer 330. The trade-off between optical transparency, conductivity and security cannot be achieved but the AZO layer is simply added to the known antireflective coating. The optically clear coating 310 of the present disclosure is expected to reduce surface reflectivity to low values over extended spectral regions in order to be highly effective while maintaining proper color balance.

It should further be considered that the reflection spectrum is already obtained when all

lens surfaces

111, 112, 113, 114 and especially the front surface 111 and the

back surface

113, 114 have been coated with the optically transparent coating 310.

The above values ensure that the reflectivity of the lens body with the optically clear coating 310 is below 0.08 as shown in the graphs in fig. 2-7. These values provide a good indication of the above-mentioned trade-off between maximum optical transparency and optimal electrical conductivity of the optically transparent coating 310 once disposed on the body 110. When designing a specific coating of the present invention with the above four layers, it will be considered that it has eight degrees of freedom (four thicknesses and four refractive indices), and thus there may be different options within the same general inventive concept. It has been found that thinner layers perform better at the wavelength invention (they reflect less), but for the AZO layer 330, for example, a greater thickness is needed to have good conductivity in order to achieve the desired power density. Furthermore, with SiO ₂ In the case of TiOx, the more extreme the refractive index is (higher or lower than the high refractive index), a smaller thickness can be used than what happens.

The camera module 200 further comprises a cartridge housing or lens assembly holder 210. The cartridge housing 210 is configured for at least partially receiving the lens body 110 and being secured therein by adhesive means, such as glue, as will be described further below.

Current is supplied to the optically transparent coating 310 through the conductor 450 by means of the power supply 400, as shown in fig. 10A to 10C, 11A to 11B, and 12. In the examples shown in the figures, power supply 400 is part of or connected to the electronics carrier described above, which includes a Printed Circuit Board (PCB) 460 disposed within cartridge housing 210. In the example shown in fig. 10B and 11A, the power supply 400 is disposed outside the cartridge housing 210, such as in a Camera Monitoring System Electronic Control Unit (CMSECU), or behind the CMS display, in a vehicle digital rearview mirror system. In this case, power is supplied directly from the ECU to the heating element 300 or through the camera cable or through the over the air (PoC) cable for simultaneous transmission of power and high resolution analog video signals and OSD control signals through a single coaxial cable.

In the example disclosed herein, the power supply 400 supplies 12V. Thus, a rapid increase in temperature in the lens body 110 from-10 ℃ to 0 ℃ by Joule effect in 8-10s is obtained. For this purpose, the optically transparent coating 310 has a resistance of 100-1500 ohms and a power density of 200-3000W/m ² In particular 250-2000W/m ² A good compromise is presented between a rapid heating process and safety.

In the example shown, the conductor is a copper cable 450 for feeding electrical current to the optically clear coating 310 for appropriate resistive heating of the lens body 110 to remove any water-based covering that may be attached thereto. The conductor 450 is attached to the optically transparent coating 310 and electrically connected to the optically transparent conductive layer 330 by a suitable attachment means, such as glue as described above. Attaching the device in fluid form prior to curing is preferred as good attachment and electrical contact with the conductor 450 in the heating element 300 is ensured. In the case where the optical axis O is arranged, the transparent adhesive is most preferable. One example of a preferred attachment means is a device having a substrate made of epoxy and conductive particles, such as silver particles.

As shown in fig. 11A-11B and 12, barrel 119 of lens assembly 100 includes the above-described passage 220 for conductor 450 to pass through. Channel 220 extends within barrel 119 such that a first end of conductor 450 may be electrically connected to power supply 400 and a second end of conductor 450 may be electrically connected to optically transparent conductive layer 330.

In the example of fig. 10A, the channel is arranged to extend through a barrel 119 in the lens assembly 100. In the example of fig. 10B, the passage is arranged to extend from the outside of the front case of the camera module 200. In the example of fig. 10C, the channels are arranged to extend through lateral sides of the lens assembly 100.

The arrangement of the channels 220 within the barrel 119 shown in fig. 10A to 10C or alternatively within the cartridge housing 210 shown in fig. 11A to 11B is advantageous in that light from outside the lens body 110 is suitably guided through the different lens elements until reaching the image sensor 470 where it is converted into a signal that will form an image to be displayed on the screen. Due to the arrangement of the channel 220, the light beam does not impinge on the conductor 450, so that there is no interference of the light beam and therefore no interference with the captured image.

As shown in fig. 11A to 11B, the passage 220 in the barrel housing 210 of the camera module 200 through which the conductor 450 passes extends within the barrel housing 210 toward the lens body 110 so that a first end of the conductor 450 may be electrically connected to the power supply 400 and a second end of the conductor 450 may be electrically connected to the optically transparent conductive layer 330.

One end of the passage 220 opens into an inner space defined by the inner wall of the cartridge housing 210. The opposite end of the channel 220 may be disposed in the interior space and optionally near the power supply 400.

The camera module 200 may include an external optical element and one or more internal optical elements. The body 110 may be part of at least one of the external optical element and the internal optical element.

A space may be formed between the external optical element and the one or more internal optical elements. The external optical element may be a protective external cover 150 as shown in fig. 11A. The protective outer cover 150 may be made of, for example, plastic or glass disposed in the lens assembly 100, which is configured to protect the lens body 110 from external elements such as dust, water, and the like. In some other examples, the external optical element may be an internal glass or plastic optical element forming part of the camera, such as the cover 150 of the barrel 119 or the lens itself. In any case, such external optical elements may become dirty due to, for example, dust accumulation, mud splash, malicious smearing, and the like. As a result, the image area covered by the contaminants cannot provide proper image data.

Lens barrel 119 is configured and dimensioned to position and align

optical lens elements

110a, 110b, 110c, 110d, 110e, 110f of lens assembly 100. For example, lens barrel 119 can include mounting features sized and configured to engage and position a plurality of internal optical system elements (e.g., one or more fixed lens elements, shutter system elements, covers, etc.). In this example, the internal optical elements (e.g., lenses) and the external optical elements of the camera module 200 may be fixed (directly or indirectly) to the cartridge housing 210. The inner lens element may be spaced a predetermined distance relative to the outer optical element.

The external optical element, such as the cover 150 and/or the first lens element 110a described above, may be substantially circular, but some other shape is also possible. The external optical element may be coupled to the inner surface of cartridge housing 210 at or near the distal end of cartridge housing 210, so that in use, the external optical element closes the top of cartridge housing 210. The cap 150 may have, for example, a threaded coupling with the top of the cartridge housing 210. The cartridge housing 210 may be a single piece, or it may comprise multiple pieces.

The inner optical element (e.g., the lens body 110) may be spaced a predetermined distance relative to the outer optical element (e.g., the cover 150). In examples where the external optical element is a first lens element 110a and the internal optical element is another lens (e.g., a second lens element 110 b), the distance between the external optical element and the internal optical element may be less than 1.5mm. However, in examples where the external optical element is a cover 150, the distance relative to the internal optical element may be, for example, between 1cm and 2 cm.

In fig. 11A, the cartridge housing 210 extends over the lens assembly 100 and is provided with the above-described cover 150 (also referred to herein as an optical element). In this example, the external optical element is the cover 150 and the lens assembly 100 is the internal optical element.

The external or internal optical element is an optically transparent member through which the optical axis O extends.

When the cover 150 is not provided, the external optical element is the first lens element 110a, and the other lens elements 110b to 110f are the internal optical elements.

When the cover 150 is provided, as in the example shown in fig. 11A, the power supply 400 is outside the cartridge housing 210 of the camera module 200 due to the high power demand, such as in the ECU of a digital rearview mirror.

Specifically, fig. 11A-11B of the drawings show the conductor 450 extending through the channel 220 extending through the cartridge housing 210. In particular, fig. 11A shows a camera module 200 having the cover 150 or an external optical surface to which an optically transparent coating 310 is applied. Thus, in the example of fig. 11A, the lens body 110 is devoid of the optically clear coating 310. In the example of fig. 11B and 12, the camera module 200 is not provided with the cover 150, so that the lens body 110 has the optically transparent coating 310. Several examples of locations of the lens body 110 where the optically clear coating 310 can be applied are shown in fig. 8A-8E, as described above.

Conductors 450 each have a first end connected to power supply 400 and a second end connected to optically clear coating 310. Optically clear coating 310 is disposed between an external optical element (e.g., cover 150) and an internal optical element (e.g., lens body 110). Thus, the second end of the conductor 450 is disposed between the outer optical element and the inner optical element. When the cover 150 is not provided, the second ends of the optically transparent coating 310 and the conductor 450 are also between at least a portion of the outer optical element and at least a portion of the inner optical element.

When the contamination in the external optical element is excessive or there is an ice sheet thereon, the camera module 200 may produce an image of insufficient quality. Thus, it may be necessary to determine when the external optical element becomes too dirty in order to perform a corresponding corrective action, such as for example the activation of an automatic cleaning system, the triggering of an alarm for manual cleaning, etc.

For this purpose, a speckle detection system 500 as disclosed in US20190391075 is provided in the camera module 200 shown in the example of fig. 12. The speckle detection system 500 includes one or more light sources 510 configured to emit light toward an external optical element, such as the lens body 110 of the cover 150. The outer optical element then reflects the light from the

light sources

510, 520 when the spot is on the outer surface of the outer optical element. The light receiver 520 is provided to receive light reflected by the lens body 110 or the cover 150 to detect speckle on the outer surface of an external optical element (e.g., the lens body 110). The optical receiver 520 may include a broadband detector comprising an infrared detector configured to operate at 700 nm. Further, the one or more light sources may produce a predetermined emission wavelength centered around the absorption band of the atmosphere, e.g., wavelengths at or near 780nm, 940nm, 1130nm, 1400nm, and 1900 nm.

The spot detection system 500 includes an optical fiber 550 connected to an electronic carrier, and in particular to a printed circuit board 460. One optical fiber 550 is located at or near the optical transmitter 510 and the other optical fiber 550 is located at or near the optical receiver 520. One end of the optical fiber 550 is positioned between the external optical element and the internal optical element. The reflected light beam from the outer surface of the external optical element is received via the optical fiber 550 towards the light receiver 520.

More specifically, one end of the optical fiber 550 is located between the first lens element 110a and the second lens element 100b, is the first lens element 110a which is the outermost lens element including the outer surface, and the second lens element 110b may be disposed below the first lens element 110 a. Further, the other end of the optical fiber 550 is located in a different location of the other optical fiber 550, but still located between the first lens element 110a and the second lens element 110 b.

As shown in fig. 12 of the drawings, at least a portion of the channel 220 may extend through the lens assembly 100, such as through the lens barrel 119, or at least a portion of the channel 220 may extend through the cartridge housing 210. In any case, the channel 220 is configured or adapted to receive at least one optical fiber 550 of the speckle detection system 500 and at least one conductor 450 of the heating element.

When optical interference is detected in the lens assembly 100 of the camera module 200, non-visible light (e.g., infrared light) of the human eye is projected by the light emitter 510 onto an external optical element (such as the cover 150, if provided) or the first lens element 110 a. Light bounced back by reflection is received due to optical interference, for example, by a spot on the outer surface of the outer optical element, such that when the received light exceeds a threshold, the controller sends a heating command. As a result of the heating instruction, power is then fed by power supply 400 through conductor 450 into optically clear coating 310 disposed on at least one surface of the external optical element. This results in an effective clearing of the optical interference present in the external optical element.

With the speckle detection system 500 described above in combination with the lens assembly 100 of the present invention, external optical elements in the camera module 200 can be effectively cleaned.

Another specific example of the camera module 200 will be described below.

The camera module 200 comprises a lens assembly 100, the lens assembly 100 comprising a lens body 110 and a heating element 300. The heating element 300 includes the optically transparent coating 310 described above, which includes an optically transparent conductive layer 330. An optically clear coating 310 is applied to at least a portion of the body 110 to resistively heat the at least a portion of the body 110 when an electrical current is passed through the optically clear conductive layer 330 to remove any water-based obstructions that may adhere to the body 110.

In this further example, the optically transparent conductive layer 330 can include at least an aluminum-doped zinc oxide layer. Optically transparent coating 310 further comprises at least one optically transparent back layer 320 disposed between lens body 110 and optically transparent conductive layer 330 and at least one electrically conductive precursor layer 340. The optically transparent back layer 320 comprises at least one high refractive index layer 321 having a refractive index higher than 1.65 and at least one low refractive index layer 322 having a refractive index lower than 1.65, wherein the high refractive index layer 321 comprises a metal oxide, preferably a metal oxide with low or no electrical conductivity, such as titanium oxide (TiOx), and the low refractive index layer 322 comprises an optically transparent dielectric material, such as silicon dioxide (SiO @) ₂ ). Optically transparent coating 310 further comprises at least one optically transparent front layer 340 disposed on optically transparent conductive layer 330, wherein at least one optically transparent front layer 340 has a refractive index lower than 1.65.

In this example, high refractive index layer 321 is 2-60nm thick, low refractive index layer 322 can be 5-200nm thick, and optically transparent front layer 340 is 5-600nm thick. More optionally, the optically transparent conductive layer 330 has a thickness of 10-1000nm.

In this example, it is preferred that the optically clear coating 310 have a thickness of 200-3000W/m ² To heat the lens body 110 within seven minutes to melt ice at-18 c adhered to the front surface of an optical element, such as the lens body 110, preferably within 8-10 seconds when the ice is at-10 c. In addition, out ofFor safety reasons, the optically clear coating 310 does not exceed 60 ℃. Furthermore, once optically clear coating 310 is applied to an optical element (such as lens body 110), the normalized reflectance is below 0.03, preferably below 0.02, in the human visible electromagnetic spectrum. This is because once the optically clear coating 310 has been applied, the optical element (such as the lens body 110) has reduced the reflectivity by at least a factor of four. It is also preferred that the optically transparent conductive layer 330 includes at least an aluminum-doped zinc oxide layer having a thickness of 20-600 nm. The optically transparent coating 310 can further include at least one optically transparent back layer 320 disposed between the lens body 110 and the optically transparent conductive layer 330, and at least one electrically conductive front layer 340 disposed on the aluminum doped zinc oxide (AZO) layer. The AZO layer 330 may be at least twice as thick as the optically transparent back layer 320. Further, the front layer 340 may be at least twice as thick as the optically transparent back layer 320.

In this case, the lens body 110 may include a plurality of

lens elements

110a, 110b, 110c, 110d, 110e, 110f, and the

lens elements

110a, 110b, 110c, 110d, 110e, 110f include a first lens element 110a, and the first lens element 110a includes a front surface 111,

rear surfaces

113, 114, and a side surface 112. The front surface 111 of the first lens element 110a is an outer surface which, in use, may be at least partially surrounded by the external environment of the camera module 200. This is because the outer surface of the first lens element 110a may be the surface of the lens assembly 100 that is furthest from the image sensor 470 when the lens assembly 100 is attached to the camera module 200. The

rear surfaces

113, 114 include a first portion 113 substantially perpendicular to the optical axis O and a second portion 114 as a curved portion. The side surface 112 abuts the front surface 111 and the

rear surfaces

113, 114. Optically clear coating 310 is applied to at least a portion of one or more of front surface 111, side surface 112, and back surfaces 113, 114. In particular, the optically transparent coating 310 is disposed on two surfaces of the lens body 110, and more preferably, the optically transparent coating 310 is disposed on two mutually adjacent surfaces of the lens body 110. More preferably, the optically transparent coating 310 is disposed on at least a portion of the surface of the lens body 110 through which the lens optical axis O passes, and on at least a portion of the surface of the lens body 110 through which the lens optical axis O does not pass. For example, optically clear coating 310 can be applied to at least one of:

(i) A portion of a front surface 111 of the body 110 and a portion of a side surface 112 of the

lens elements

110a, 110b, 110, c, 110d, 110e, 110 f; or

(ii) A portion of the first portion (113) of the rear surface and a portion of the second portion (114) of the rear surface.

In this example, the heating element 300 may further comprise a conductor 450, preferably at least two conductors 450, for electrically connecting the above-mentioned power supply 400 to the transparent conductive layer 330 for feeding an electric current to the transparent conductive layer 330. The conductor 450 is part of the heating element 300 and is arranged to extend within the cartridge housing 210 towards the lens body 110.

In this particular example of the present camera module 200, means for attaching the conductor 450 to the optically transparent coating 310 are provided for electrically connecting the conductor 450 to the optically transparent conductive layer 330. The attachment means may be arranged on any surface of the lens body 110 not traversed by the optical axis O, in particular on the first portion 113 and/or the side surface 112 of the rear surface. More optionally, the attachment means is a conductive adhesive. The optically transparent coating 310 is arranged on two mutually adjacent surfaces of the lens body 110, and the attachment means is arranged on a surface of the two mutually adjacent surfaces of the lens body 110 which is not penetrated by the optical axis O.

In yet another particular example, the camera module 200 includes an optically transparent outer optical element, an optically transparent inner optical element, a camera module housing, an electronics carrier 460, a heating element 300, and a lens assembly 100, the lens assembly 100 including a lens body 110 that can be part of at least one of the outer optical element and the inner optical element.

Heating element 300 includes an optically transparent coating 310, and optically transparent coating 310 includes an optically transparent conductive layer 330. Optically clear coating 310 is applied to at least a portion of the external optical element to resistively heat the at least a portion of the optical element when current flows through optically clear conductive layer 330, thereby removing any water-based obscuration that may adhere to the external optical element. At least one conductor 450 is provided for supplying current to the optically transparent conductive layer 330 to feed current to the optically transparent conductive layer 330.

The camera module 200 may include a protective outer cover 150 for covering and protecting the lens assembly 100. The cover 150 may be made of plastic, glass, or any other suitable material. If the camera module 200 includes the cover 150, the cover 150 corresponds to the external optical element and the lens body 110 corresponds to the internal optical element. If the camera module 200 does not include a cover, the first lens element 110a of the body 110 corresponds to the external optical element and the second lens element 110b of the body 110 corresponds to the internal optical element.

Thus, the external optical element may be at least one of the protective outer cover 150 and the lens assembly 100, which is spaced a predetermined distance relative to the internal optical element.

The camera module housing further comprises a cartridge housing 210, the cartridge housing 210 being configured for at least partially receiving the external optical element and the internal optical element. The power supply 400 is located in at least one of:

(i) Inside the camera module housing, in particular on an electronic carrier such as a printed circuit board 460; and

(ii) Outside the camera module housing, in particular below the display, the display provides a displayed image based on the captured image taken by the camera module 200. The display may be part of a digital mirror system, such as a lateral digital mirror system.

In any case, the power supply 400 is configured to supply current to the optically transparent conductive layer 330. The electronic carrier 460 comprises an image sensor 470 which is optically aligned with the lens assembly 100. The camera module housing may comprise at least one channel 220 for the passage of a conductor 450. Preferably, at least one channel 220 extends through cartridge housing 210.

The process for applying optically clear coating 310 to an external optical element (as the external optical element of protective cover 150 or lens body 110) includes the steps of:

a) Depositing a solution onto the external optical element, the solution comprising a salt;

b) Evaporating the solution at a temperature sufficient to leave a residue of the salt;

c) Heating the residue at a predetermined temperature for a period of time sufficient to convert the deposit into a layer of predetermined thickness;

d) Repeating steps a-c to obtain:

(i) At least one high refractive index layer 321 comprising a metal oxide having a low or no refractive index greater than 1.65 and a thickness between 2-60nm,

(ii) At least one low refractive index layer 322 comprising an optically transparent dielectric material having a refractive index below 1.65 and a thickness between 5-200nm,

(iii) An optically transparent conductive layer 330 comprising an optically transparent conductive material having a refractive index higher than 1.65 and a thickness between 10-900nm, and

(iv) At least one optically transparent front layer 340 comprising an optically transparent dielectric material having a refractive index below 1.65 and a thickness between 5-600 nm.

The optically transparent coating 310 has a resistance of 100-1500 ohms and a power density of 200-3000W/m ² And the external optical element to which the optically clear coating 310 is applied has a normalized reflectance of less than 0.03 for the electromagnetic spectrum visible to the human eye. Furthermore, the optically transparent conductive layer 330 is deposited with dimensions larger than the

other layers

321, 322, 340, so that in use a portion of said optically transparent conductive layer 330 is uncovered, which is adapted to receive an end of a conductor and to apply an attachment means (adhesive) to ensure mechanical bonding and electrical connection.

The process for applying the optically clear coating 310 can further include:

e) The attachment means is applied such that the conductors are attached to optically clear coating 310 and electrically connected to optically clear conductive layer 330.

Preferably, the attachment means is a fluid conductive adhesive, which may be optically transparent, and wherein the first end of the conductor is attached to the uncovered portion of the optically transparent conductive layer 330.

The process for applying the optically clear coating 310 can further include:

f) The attachment means is cured by applying a predetermined air, light or temperature such that the first pre-cured state is liquid prior to curing and then the adhesive is in a second cured state which is no longer liquid once curing has been applied.

To manufacture lens assembly 100, an optically clear coating 310 is applied to at least a portion of one or more of front surface 111, side surface 112, back surface 113, and back surface 114 of lens body 110. The optically transparent coating 310 comprises the above-described high refractive index titanium oxide (TiOx) layer 321 applied to one or more of the

portions

111, 112, 113, 114 of the lens body 110, followed by a low refractive index silicon dioxide (SiO) applied to the high refractive index titanium oxide (TiOx) layer 321 ₂ ) Layer 322, and application to the low refractive index silicon dioxide (SiO) ₂ ) Transparent conductive aluminum doped zinc oxide (AZO) layer 330 of layer 321. More specifically, as low refractive index Silica (SiO) ₂ ) A front layer 340 of layers is disposed on the transparent conductive aluminum doped zinc oxide (AZO) layer 330.

To assemble the camera module 200 to the lens assembly 100, the lens body 110 with the optically transparent coating already applied thereon is at least partially inserted into the cartridge housing 210. The lens body 110 is then moved accurately into proper alignment with the image sensor 470, for example by a 5-axis robot. In this manner, the image sensor 470 is then coupled to the PCB460 by suitable optical communication and aligned with the lens assembly 100 such that an image of the exterior of the vehicle is properly captured.

Examples of the present camera module 200 with the lens assembly 100 and a method for manufacturing the lens assembly 100 have been disclosed herein. However, other alternatives, modifications, uses, and/or equivalents thereof are possible. For example, unless otherwise specified, applying the transparent conductive coating 310 to the body 110 can involve applying the transparent conductive coating 310 directly to the body 110, but in some cases it can involve applying the transparent conductive coating 310 indirectly to the body 110. The latter may occur when an intermediate layer is present in the lens body 110, for example, when a cover glass is provided onto the lens body 110, the transparent conductive coating 310 is in this case applied to the cover glass and is therefore not applied directly to the lens body 110.

The scope of the present disclosure should not be limited by the particular examples disclosed herein, but should be determined only by a fair reading of the claims that follow. Any reference signs placed between parentheses in the claims and associated with the drawings are intended for increasing the readability of the claims and should not be construed as limiting the scope.

Claims

1. A lens assembly (100) comprising a lens body (110) and a heating element (300), wherein the heating element (300) comprises an optically transparent coating (310), the optically transparent coating (310) comprising an optically transparent conductive layer (330), wherein the optically transparent coating (310) is applied to at least a portion of the lens body (110) for resistively heating the at least a portion of the lens body (110) when an electrical current is passed through the optically transparent conductive layer (330) to remove any water-based obstructions that may adhere to the lens body (110).

2. Lens assembly (100) according to claim 1, wherein the optically transparent conductive layer (330) comprises zinc oxide doped with at least aluminum.

3. Lens assembly (100) according to claim 1 or 2, wherein the optically transparent coating (310) further comprises at least one optically transparent back layer (320) arranged between the lens body (110) and the optically transparent electrically conductive layer (330).

4. Lens assembly (100) according to claim 3, wherein the optically transparent back layer (320) comprises at least one high refractive index layer (321) having a refractive index higher than 1.65 and at least one low refractive index layer (322) having a refractive index lower than 1.65, wherein the high refractive index layer (321) comprises a metal oxide, preferably titanium oxide, and wherein the low refractive index layer (322) comprises silicon dioxide.

5. Lens assembly (100) according to claim 1 or 2, wherein the optically transparent coating (310) further comprises at least one optically transparent front layer (340) arranged on the optically transparent electrically conductive layer (330), wherein the optically transparent coating (310) has a refractive index lower than 1.65.

6. Lens assembly (100) according to claim 1 or 2, wherein the thickness of the optically transparent electrically conductive layer (330) is 10-1000nm.

7. Lens assembly (100) according to claim 4, wherein the high refractive index layer (321) has a thickness of 5-30nm, wherein the low refractive index layer (322) has a thickness of 9-90nm, and wherein the optically transparent front layer (340) has a thickness of 10-200nm.

8. Lens assembly (100) according to claim 1 or 2, wherein the lens body (110) comprises a plurality of lens elements comprising at least one lens element comprising a front surface (111), a rear surface (113, 114) and a side surface (112), wherein the front surface (111) is arranged facing away from the rear surface (113, 114), the rear surface (113, 114) comprises a first portion (113) and a second portion (114), the first portion (113) being substantially perpendicular to the optical axis (O) of the lens body (110), the second portion (114) being a curved portion, wherein the side surface (112) abuts the front surface (111) and the rear surface (113, 114), and wherein the optically transparent coating (310) is applied to at least a portion of one or more of the front surface (111), the side surface (112) and the rear surface (113, 114).

9. Lens assembly (100) according to claim 8, wherein the optically transparent coating (310) is applied to at least one of:

(i) A portion of the front surface (111) and a portion of the side surface (112); or alternatively

(ii) A portion of the first portion (113) of the rear surface (113, 114) and a portion of the second portion (114) of the rear surface (113, 114).

10. Lens assembly (100) according to claim 8, wherein the lens assembly further comprises a conductor (450) for supplying an electrical current to the optically transparent electrically conductive layer (330) for resistive heating of at least a part of the lens body (110).

11. Lens assembly (100) according to claim 10, wherein the lens assembly further comprises attachment means for attaching the conductor (450) to the optically transparent coating (310) such that the conductor (450) is electrically connected to the optically transparent conductive layer (330).

12. Lens assembly (100) according to claim 11, wherein the attachment means are arranged on the first portion (113) of the rear surface (113, 114) and/or the side surface (112).

13. A camera module (200) for a motor vehicle, the camera module (200) comprising an optically transparent outer optical element, an optically transparent inner optical element and a lens assembly (100), the lens assembly (100) comprising:

-a lens body (110) being part of at least one of the external and internal optical elements;

-a heating element (300) comprising an optically transparent coating (310), the optically transparent coating (310) comprising an optically transparent electrically conductive layer (330), wherein the optically transparent coating (310) is applied to at least a portion of the lens body (110) for resistively heating the at least a portion of the lens body (110) when an electrical current is flowing through the optically transparent electrically conductive layer (330) to remove any water-based obstructions that may adhere to the lens body (110);

-a conductor (450) for supplying an electrical current to the optically transparent, electrically conductive layer (330) for feeding an electrical current to the optically transparent, electrically conductive layer (330); and

-a camera module housing comprising a cartridge housing (210) configured for at least partially receiving the lens body (110), and wherein the camera module housing comprises at least one channel (220) for passage of the conductor (450).

14. The camera module (200) of claim 13, wherein the at least one channel (220) is arranged to extend within the cartridge housing (210) towards the lens body (110).

15. A method for manufacturing a lens assembly (100), the lens assembly (100) comprising a lens body (110) and a heating element (300), wherein the method comprises applying to at least a portion of one or more of a front surface (111), a rear surface (113, 114) and a side surface (112) of the lens body (110):

-at least one high refractive index layer (321);

-at least one low refractive index layer (322) applied onto the high refractive index layer (321); and

-at least one aluminum-doped zinc oxide layer (330) applied onto the low refractive index layer (322).